# -*- coding: utf-8 *-*

#   This file is part of Sql-Rice.
#
#    Sql-Rice is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 3 of the License, or
#    (at your option) any later version.
#
#    Sql-Rice is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with Sql-Rice; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

import uuid


class InvalidOperationException(Exception):
    pass


class ThreadFlag(object):

    def __init__(self):
        self.__locked = False
        self.__key = None
        self.__flag = None

    def lock(self):
        if self.__locked:
            raise InvalidOperationException('Object Already Locked')
        self.__key = uuid.uuid4()
        self.__locked = True
        return self.__key

    def set_flag(self, key, flag):
        if self.__key == key:
            self.__flag = flag
        else:
            raise InvalidOperationException('Ivalid UUID for object')

    def get_flag(self):
        return self.__flag
